Explosion Protection for the Cement Industry

When the Czech branch of a globally recognized leader in industrial weighing, feeding, measuring and process technologies encountered technical design challenges in providing an explosion protection concept for a client, they turned to IEP Technologies Europe for an innovative and low maintenance solution. The end user, a major building materials and solutions company with plants and operations worldwide, produce a range of construction materials including cement, aggregates and ready-mix concrete for use in small, local housing developments through to large technically and architecturally challenging infrastructure projects.

The project involved the installation of a new multi-stage pre-heater process in a cement production plant located in Canada. The raw materials used in the production of cement, namely limestone together with clay or shale, are crushed to a very fine powder and blended to form what is known as “raw feed” or “raw mix”. This blended raw material is then progressively heated in the pre-heater using hot exhaust gases from the kiln before finally being transferred to the cement kiln where it reaches a temperature of approximately 1400 C to 1500 C, which is necessary to attain calcination and form larger pieces typically known as “clinker”. The clinker is then cooled before being milled to a powder to form cement. In this plant the fuel used for the burner is a sustainable “bio-mass” and the main explosion risk identified within the system is present in the form of the potential for hot particles or glowing “nests” emanating from the conveying system in addition to the possibility that ignition from the burner could be transferred up into the ducting.

Primary explosion protection

The primary explosion protection was achieved through installing multiple Hoerbiger EVN flameless explosion venting valves to specific locations within the process. The ATEX compliant EVN valve consists of a circular venting device with an integrated flame arrester.